In recent years, mobile devices (e.g., smart phones, tablet computers) have become very popular. One reason for their popularity is that they can be used nearly anywhere to perform a variety of different tasks. For instance, many of these mobile devices allow their users to exchange emails, make telephone calls, purchase items online, take photos, share comments and photos through different social network platforms, etc. These mobile devices are also very easy to share. In fact, many people share their devices with family or friends to make phone calls, to share games or applications, etc.
While such mobile devices have proved to be very useful, they often store private data (e.g., contacts, emails, private photos), or provide easy access to other sources (e.g., a social network website, an online bank) that store private data. This presents a problem when a first person wants to share a game or application on his device with a second person, but does not wish the second person to have access to his private data. This is especially problematic because the first person cannot always monitor the second person's use of his device, or even if he can, finds it awkward to do so.
The need to keep private data on a mobile device confidential is not the only motivation that prevents users from sharing their mobile devices with others. Many other reasons exist that make such sharing difficult. For instance, kids often wish to play with the mobile devices of their parents. However, while using their parents' devices, kids may inadvertently delete data (e.g., delete photos, emails, etc.) or initiate/send communications (e.g., initiate calls, send e-mails, etc.).
In addition to the need to control another's access to one's mobile device, one often needs to quickly access certain functionalities of one's device. In devices with touch screen controls, such access is often delayed because of controls that are placed on the devices to prevent inadvertent operation of the devices. For example, many devices place lock screen controls (including passcode and/or gesture controls) that are needed to gain access to all or most of the applications of the device. Such controls slow down the user's access. Also, in some cases the user has difficulty performing the operations necessitated by these controls. For instance, a user may have such difficulty when the user is busy performing other tasks (e.g., when the user is jogging, biking, etc.).